17 Jul 2003
One of the most frustrating experiences on the Web is filling out forms. When mistakes are made, the user is often left guessing what they need to correct. We’ve taken an approach that shows the user in no uncertain terms what needs to be fixed.
Most forms require validation — checks to see that required fields have been filled out with the right information. But when a mistake was made, how do you let the user know? The approaches taken by many sites leave much to be desired.
Here’s how we simplified the error screen.
We’ve provided a demo of the simplified form. Go take a look.
In addition to simply showing the form layout, we’ve also written up an example in PHP. The form validation is simple, but it’s easy to adapt this to your own validation needs or to another programming language like ASP or Perl.
<?php
// Create an empty array to hold the error messages.
$arrErrors = array();
//Only validate if the Submit button was clicked.
if (!empty($_POST['Submit'])) {
// Each time there’s an error, add an error message to the error array
// using the field name as the key.
if ($_POST['name']=='')
$arrErrors['name'] = 'Please provide your name.';
if ($_POST['email']=='')
$arrErrors['email'] = 'A valid email address is required.';
if ($_POST['phone']=='')
$arrErrors['phone'] = 'Please provide your phone number.';
if (count($arrErrors) == 0) {
// If the error array is empty, there were no errors.
// Insert form processing here.
} else {
// The error array had something in it. There was an error.
// Start adding error text to an error string.
$strError = '<div class="formerror"><p><img src="/images/triangle_error.gif" width="16" height="16" hspace="5" alt="">Please check the following and try again:</p><ul>';
// Get each error and add it to the error string
// as a list item.
foreach ($arrErrors as $error) {
$strError .= "<li>$error</li>";
}
$strError .= '</ul></div>';
}
}
?>
<style>
label {
width: 80px;
text-align: right;
float: left;
}
.formerror {
border: 1px solid red;
background-color : #FFCCCC;
width: auto;
padding: 5px 0;
}
.errortext {
padding-left: 80px;
font: bold smaller sans-serif;
}
</style>
<?php echo $strError; ?>
<form method="post" action="<?php echo $PHP_SELF; ?>">
<!--
For every form field, we do the following...
Check to see if there’s an error message for this form field. If there is,
add the formerror class to the surrounding paragraph block. The formerror
class contains the highlighted box.
Insert the contents of what the user submitted bak into the form field.
Check again to see if this field has an error message. If it does, show
the error icon and the error message next to the field.
-->
<p<?php if (!empty($arrErrors['name'])) echo ' class="formerror"'; ?>>
<label for="name">Name:</label>
<input name="name" type="text" id="name" value="<?php echo $_POST['name'] ?>">
<?php if (!empty($arrErrors['name'])) echo '<img src="/images/triangle_error.gif" width="16" height="16" hspace="5" alt=""><br /><span class="errortext">'.$arrErrors['name'].'</span>'; ?>
</p>
<p<?php if (!empty($arrErrors['email'])) echo ' class="formerror"'; ?>>
<label for="email">Email:</label>
<input name="email" type="text" id="email" value="<?php echo $_POST['email'] ?>">
<?php if (!empty($arrErrors['email'])) echo '<img src="/images/triangle_error.gif" width="16" height="16" hspace="5" alt=""><br /><span class="errortext">'.$arrErrors['email'].'</span>'; ?>
</p>
<p<?php if (!empty($arrErrors['phone'])) echo ' class="formerror"'; ?>>
<label for="phone">Phone:</label>
<input name="phone" type="text" id="phone" value="<?php echo $_POST['phone'] ?>">
<?php if (!empty($arrErrors['phone'])) echo '<img src="/images/triangle_error.gif" width="16" height="16" hspace="5" alt=""><br /><span class="errortext">'.$arrErrors['phone'].'</span>'; ?>
</p>
<p>
<input type="submit" name="Submit" value="Submit">
</p>
</form>
Thanks for the great example, both visual and the back-end code.
Even though a couple people have picked nits with the PHP you included, it’s quite valuable to be able to illustrate that it’s not a huge task to do your web forms this way, instead of the problem ways you describe at the beginning of the article.
The reason why people do forms the problem ways is because it’s easier, or it’s the first solution that comes to mind. Just showing them the outline of a better way is often enough to change their thinking. (OK, maybe I’m projecting here; it worked for me. ;-)
Nice article. I’ve been using Zope and a product called “Formulator.” There are other kits like it out there for other languages/frameworks/servers. Basically - using Formulator (or something like it), you can design a form as smart widgets - instead of just an integer field, it can be an integer field with the range of 0 to 50. I like it because it takes care of both rendering (for most of my forms, I can just use a single loop to draw all of the fields) and validation.
Lately, I’ve been doing only one of the error displays that you’ve mentioned - displaying them up top, or displaying them next to the field. And I haven’t been doing the greatest job at highlighting. I’ll start applying both inline and uptop to my code from now on, and do the highlighting.
But I highly recommend looking into a Form Helper kit. ASP.NET has the concept built in, it seems. But for other systems - it’s very helpful to be able to describe and define a form, its widgets, validation, etc, in the same place - outside of the code that will be responsible for display and validation. My applications have become a lot stronger since moving to such a system (mostly because I’d tend to be lazy/stressed and often punt on manual validation as one of those “I’ll get back to it…” things).
The PEAR library comes with an HTMLQuickForm package that allows for some useful form validation and error displaying. So far I am pretty happy with it. If you are interested check it out at: http://pear.php.net/package/HTMLQuickForm
It should get you most of the way there.
Have you been past the Google AdSense login page recently (https://google.com/adsense/)? Try entering an invalid login and see what happens. While it isn’t exactly like the suggestion here, it is awfully close :)
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Adam Kalsey
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Richard Soderberg
July 27, 2003 3:20 PM
Looks remarkably similar to the error-handling I implemented at DataBuilt, way back when. We did server-side and client-side both — should still be up on the web!